'X-Men: Apocalypse': The Secret Behind the Post-Credit Scene

This story spoils the post-credits sequence from X-Men: Apocalypse. If you want to stay unaware of what lies in the future for Fox's superhero franchise, look away now.

For those not well-versed in comic book X-Men lore, the post-credit scene in X-Men: Apocalypse might have seemed surprisingly understated: A mysterious group of men in suits wander through the military installation where Wolverine was held, taking a vial marked "Weapon X" and placing it in a briefcase that reads "Essex Corp." So far, so generic, right …? Well — not exactly.

Meet Mister Sinister.

The wonderfully over-the-top villain, who debuted in 1987's Uncanny X-Men No. 221, is yet another surprisingly long-lived threat obsessed with evolutionary processes and mutantkind (there are many in the X-canon). More importantly, he's a surprisingly long-lived threat obsessed with evolutionary processes and mutantkind whose name is Nathaniel Essex. Suddenly, everything becomes a little bit clearer.

In comic book mythology, Essex was a biologist in Victorian England who was obsessed with Charles Darwin's ideas surrounding the survival of the fittest; following the death of his first-born child, he found himself in league with Apocalypse in an attempt to locate the source of mutantkind's extraordinary abilities. (Traditionally called the "X-Gene," Essex amusingly referred to it as "the Essex Gene.") Spurned by his family and the scientific community, he becomes transformed by Apocalypse into a superhuman, choosing the name "Sinister" in tribute to his wife's last words to him ("To me, you are utterly and contemptibly sinister," for those curious).

As Sinister, he was responsible for manipulating the early life of Scott Summers, AKA Cyclops, and also creating a clone of Jean Grey with the intent that she would seduce Cyclops and bear him a child, who Sinister believed would was destined to destroy Apocalypse. He also formed a team of superhuman mercenaries known as the Marauders who, in a 1986 storyline called "Mutant Massacre," slaughtered an entire underground community of mutants because he believed they were the result of an unauthorized creation of his evolutionary theories.

Indeed, if there's one thread that follows Sinister through his comic book career, it's his single-minded devotion not merely to science, but to science that centers around his monumental ego — the belief that only he can "solve" the mysteries of evolution, and the fact that he will stop at nothing in his quest to do so. In recent years, he has created entire communities based around cloned versions of himself, experimented on mutants in an attempt to create a superior breed that combines mutant and inhuman DNA and stolen DNA samples from a group of X-Men so that he could clone his own super-team.

It's that final storyline, from the underrated 2014 Spider-Man and the X-Men series written by former Daily Show writer Elliot Kalan, that might point towards the future of the X-franchise for Fox. Does this mean that the next X-Men movie will feature the team mobilizing against Mister Sinister? Possibly — but there's also the chance that it's laying groundwork for the next Wolverine movie.